Edison as I know him, by Henry Ford, in collaboration with Samuel Crowther.

EDISON As I KNOW HIM

for a burner. My next step proved conclusively
the correctness of my former deductions.
"I decided to test out my theory by the use of
a filamentary burner and my old laboratory notebooks show that on October 21, 1879, after many
heartbreaking trials, we succeeded in carbonizing
a piece of cotton sewing thread, bent into horseshoe shape, and I had it sealed into a glass globe
from which I exhausted the air until a vacuum
up to one-millionth of an atmosphere was produced. The lamp was hermetically sealed and
then taken off the vacuum pump and put on the
electric current.
"It lighted up and in the first few breathless
minutes we measured its resistance quickly and
found that it was 275 ohms-all we wanted.
Then we sat down and looked at that lamp. We
wanted to see how long it would burn. The problem was solved-if the filament would last. We
sat and looked, and the lamp continued to burn.
The longer it burned, the more fascinated we
were.
"None of us could go to bed, and there was no
sleep for any of us for forty hours. We sat and
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